Image marking method and apparatus

ABSTRACT

In accordance with embodiments of the present disclosure, a method for marking an image projected onto a surface includes capturing a second image from the surface, detecting the existence of a marking point in the second image, and modifying the first image by placing a graphic element at a location corresponding to a location of the marking point in the second image.

BACKGROUND

Unless otherwise indicated herein, the approaches described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

Projecting images onto a screen is broadly used for presentationpurposes and the like. During a presentation, a presenter may“electronically write”, or mark, on the projected image to emphasize ona particular point or make notes for future reference. For example, whena Microsoft® PowerPoint® presentation is projected onto a screen, thepresenter may directly mark on one of the presentation slides by usingthe PowerPoint editing functions. The updated slide, which contains thepresenter's inputs, can then be projected onto the screen.

Alternatively, the presenter may rely on a screen (e.g., a white board)capable of electronically capturing his/her writings and drawings. Sucha screen may be equipped with physical-contact sensors or light sensors,and the screen can be configured to capture and display the presenterinputs. For example, suppose the screen can detect physical contact.During presentation, the presenter can use a hard object to pressagainst the screen. The signal generated by the pressing is thencaptured by the screen and utilized for making marks on the image to bedisplayed.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. These drawingsdepict only several embodiments in accordance with the disclosure andare, therefore, not to be considered limiting of its scope. Thedisclosure will be described with additional specificity and detailthrough use of the accompanying drawings.

FIG. 1 is a block diagram illustrating an example image deviceconfigured to capture marking points on an image;

FIG. 2 is a block diagram illustrating a second example image deviceconfigured to capture marking points on an image;

FIG. 3 illustrates an operational scenario in utilizing a marking deviceto place marking points on a projected image;

FIG. 4 is a flow diagram of an example process for capturing anddisplaying marks on a projected image; and

FIG. 5 is a flow diagram of an example process for calibrating,capturing and displaying marks on a projected image, all arranged inaccordance with at least some embodiments of the present disclosure.

SUMMARY

In accordance with one embodiment of the present disclosure, a methodfor marking an image projected onto a surface includes capturing asecond image from the surface, detecting the existence of a markingpoint in the second image, and modifying the first image by placing agraphic element at a location corresponding to a location of the markingpoint in the second image.

In accordance with another embodiment of the present disclosure, amethod for marking a first image projected onto a surface includescapturing a second image from the surface, detecting a marking point inthe second image, determining a location of the marking point in thesecond image, modifying the first image to generate a third image byplacing a graphic element at a location corresponding to a location ofthe marking point in the second image, and projecting the third image tothe surface to replace the first image.

In accordance with a further embodiment of the present disclosure, asystem configured to mark an image includes an image projecting partconfigured to project a first image to a surface, an image capturingpart configured to capture a second image from the surface, and an imageprocessor coupled with the image projecting part and the image capturingpart. The image processor is configured to detect a marking point in thesecond image and to modify the first image to generate a third image byadding a graphic element at a location corresponding to a location ofthe marking point in the second image.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe Figures, can be arranged, substituted, combined, and designed in awide variety of different configurations, all of which are explicitlycontemplated and make part of this disclosure.

This disclosure is drawn, inter alia, to methods, apparatus, computerprograms and systems related to marking on an image. Throughout thedisclosure, the term “marking device” broadly refers to a device capableof highlighting an area of interest in an image or causing the area ofinterest to be marked. The term “marking point” broadly refers to aposition in an image identified by a marking device that is to bemarked. “Marking” an image generally refers to modifying the image toinclude a graphic element (e.g., line, character symbol, and others) ina designated area of the image. The graphic element may have variousdegrees of transparency when placed over the designated area of theimage.

An image device having a projecting part can project a first image to asurface for purposes such as, without limitation, presentation. With animage capturing part of the image device configured to capture a secondimage from the surface, the light emitted from a marking device may becaptured by the image device as a marking point. In someimplementations, the marking point may correspond to a point on thesurface, from which the light emitted from the marking device is orappears to be reflected. In other implementations, the marking point maycorrespond to a point on the surface that a pen-like marking devicepresses against. The captured second image may be processed to detectthe existence of the marking point and the location of the marking pointin the second image.

After having ascertained the existence and the location of the markingpoint, the image device can modify the first image by placing a graphicelement at a location in the first image, which corresponds to thelocation of the detected marking point in the second image. In oneimplementation, the modified first image is then projected to thesurface to replace the original first image. In other words, thisprocess allows the marking device to potentially leave marks on thefirst image. Moreover, by repeating the process of capturing markingpoints and modifying the first image, the image device allows writingsand drawings to be marked on the first image.

FIG. 1 is a block diagram illustrating an example image deviceconfigured to capture marking points on an image, in accordance with atleast some embodiments of the present disclosure. The image device 180includes, among other things, an image processor 160, and a memory 170,which may be internal or external to the image device 180. The imagedevice 180 may include an image projecting part 140, an image capturingpart 150, and optionally a filter 130. The image processor 160 controlsthe operation of the image device 180 and may direct the imageprojecting part 140 to project a first image to the surface 110. Whenthe image device 180 is in a marking mode, the image processor 160 mayalso instruct the image capturing part 150 to capture a second imagefrom the surface 110 and process the captured second image to detect amarking point contained therein. Based on the detected marking point,the image processor 160 may also utilize the memory 170 to mark thefirst image and project the marked first image to the surface 110.

With the image device 180 in the marking mode and with the capturedsecond image, the image processor 160 in one implementation may proceedto determine the location of the marking point in the second image andmodify the first image by placing a graphic element at a locationcorresponding to the location of the detected marking point in thesecond image. Then, the image processor 160 may instruct the imageprojecting part 140 to project the modified first image to the surface110.

The image device 180 may be placed in the marking mode in a number ofways. For example, in response to receiving a request to mark via awired or wireless connection, the image device 180 may switch to themarking mode. Alternatively, the image device 180 may search for certainlight characteristics (e.g., a light in a certain light spectrum). Whenthe characteristics are detected, the image device 180 may switch to themarking mode. The marking mode may also be switched off in a similarmanner. For example, the image device 180 may receive a request toswitch off its marking mode. Alternatively, the image device 180 mayswitch off its marking mode when the light characteristics are notdetected for a period of time. In the non-marking mode, the image device180 may be configured to simply project unaltered images.

In one implementation, the image projecting part 140 is configured toproject an image to an area of the surface 110. Such an area is referredto as a “projecting field.” The image projecting part 140 may includeadditional hardware components and/or software functions to adjust theprojecting field. For example, the image projecting part 140 may beconfigured to increase/decrease the size of the projecting field, movethe projecting field to a different location on the surface, and/oradjust the color, contrast, and focus of the image being projected.

In one implementation, the image capturing part 150 is configured tocapture images and/or videos from the surface 110. One example of theimage capturing part 150 may be a camera with a lens, a charged-coupleddevice (CCD), or a complementary metal oxide semiconductor (CMOS)sensor. The image capturing part 150 may also be a camcorder adapted forcapturing, processing, and storing videos. The captured image and/orvideo data may then be sent to the image processor 160 for furtherprocessing. The image capturing part 150 has a “viewing field”,representing an area on the surface 110 that can be viewed and capturedfrom the perspective of the image capturing part 150. The viewing fieldmay also be similarly adjusted as the projecting field of the imageprojecting part 140. In one implementation, the viewing field and theprojecting field may be aligned through a calibration process. Thecalibration process ensures that a projected image projected by theprojecting part 140 and a captured image captured by the capturing part150 can be meaningfully compared and/or processed to detect markingpoints.

In one implementation, the surface 110 is a surface for displayingimages or videos projected from the image projecting part 140. Thesurface 110 may be a surface having proper roughness and color so that alight projected onto it can be appropriately reflected in certainviewing directions. In one example, the surface 110 may be a projectingscreen designed to allow an image, being projected from one side, to beviewable from one or both sides of the screen. In other examples, thesurface 110 may be an uneven, curvy, and/or non-flat surface, such as,without limitation, a section of a white wall in a room, a floor, aceiling, an outside wall of a building, or a reflective liquid surface.Further, the surface 110 is not required to be equipped or coupled withany type of electronic or light sensors.

In one implementation, the marking device 120 may emit a light beam 112(e.g., infrared light, laser, or other spectrums of light) towards thesurface 110. When the light beam 112 hits the surface 110, the light maybe reflected in one or more directions and may be captured by the imagecapturing part 150. When the image device 180 is in the marking mode,the point from which the light is reflected and captured is considered amarking point. When the light beam 112 is moved from a first location toa second location on the surface 110, the marking point is alsoconsidered to have moved from the first place to the second place.

The marking device 120 may emit a light that is in a human-visiblespectrum or a human-invisible spectrum. When the light is in thehuman-invisible spectrum (e.g., infrared light) and the marking mode isenabled, the image device 180 may utilize its marking-point detectingfunction to detect the location of the invisible marking point on thesurface 110 and utilize its image-modification function to place agraphic element on the image to be projected. As a result, the projectedgraphic element in effect turns the human-invisible marking point into avisible one.

On the other hand, when the marking device 120 emits a human-visible andimage-device-detectible light beam, the marking device 120 may be usedas a laser pointer. In one implementation, with a press of a buttonsending a signal to the image device 180 to switch on the marking mode,the image device 180 may start marking of the image to be projectedbased on the movement of the light beam. The details of marking an imageare further described below.

In one implementation, a light filter 130 may be installed in front ofthe image capturing part 150 to filter out and/or allow in certainspectrums of light emitted from the marking device 120. For example, ifthe marking device 120 utilizes infrared light for marking a projectedimage, then the light filter 130 may be configured to allow infraredlight emitted from the marking device 120 to be passed through the lightfilter 130 and to be captured by the image capturing part 150. Thus, thelight filter 130 may simplify the detecting of marking points byevaluating whether there is any light with sufficient intensity. Ifthere is no substantial amount of light passing through, then no markingpoint may be present. On the other hand, if the light passing throughthe light filter 130 comes mostly from a certain location and withsufficient intensity, then a marking point may be present.

According to one embodiment of the present disclosure, the imageprojecting part 140 and the image capturing part 150 can be integratedinto the image device 180. The image device 180 can be implemented as aportable device such as a mobile phone, a personal data assistant (PDA),a personal media player device, a wireless web-watch device, a personalheadset device, an application specific device, or a hybrid device thatinclude any of the above functions. The image device 180 can beimplemented as a personal computer including both laptop computer andnon-laptop computer configurations, or as an image projector. The imagedevice 180 can also be implemented to project high intensity light anddisplay/capture images in a relatively bright environment. In onealternative embodiment, the image projecting part 140 and/or the imagecapturing part 150 may be external to the image device 180. In thiscase, these external image projecting and image capturing devices may becoupled with the image device 180 to perform the similar functions asdiscussed above. In yet another alternative embodiment, the imageprojecting part 140 and the image capturing part 150 may be a singlecomponent that is capable of projecting and capturing images.

FIG. 2 is a block diagram illustrating a second example image deviceconfigured to capture marking points on an image, in accordance with atleast some embodiments of the present disclosure. The surface 110 andthe image device 180 of FIG. 2 are similar to the ones illustrated inFIG. 1. In FIG. 2, the marking device 220 utilizes a different approachin causing marking points to be generated. Instead of emitting a lightbeam, the marking device 220 of FIG. 2 includes a light source thatemits light in all directions. In operation, the marking device 220 maybe placed between the surface 110 and the image device 180. For example,the marking device 220 may be held in front of the image capturing part150. The placement of the marking device 220 may also be adjusted toavoid blocking the image projected from the image projecting part 140.

In one scenario, when the marking device 220 is placed in front of theimage capturing part 150, the light emitted from the marking device 220may be perceived as if the light were reflected from the surface 110from the viewing field of the image capturing part 150. In other words,by viewing along a viewing path 230, the light from the marking device220 appears the same as if light is reflected from a location on thesurface 110, such as the location of a marking point 210. The imagecaptured by the image capturing part 150 would still contain thismarking point 210. Moreover, the marking device 220, which is positionedbetween the image projecting part 140 and the surface 110, may blocklight emitted from the image projecting part 140 and leave a shadow onthe surface 110. The shadow of the marking device 220 may be used tocalibrate the placement of the marking point 210, before the lightsource of the marking device 220 is turned on. For example, a pen-shapemarking device 220 may leave a pen-shape shadow on the surface 110.Thus, if the light source is on the tip of the marking device 220, byadjusting the marking device 220 in front of the image projecting part140, the shadow tip of the marking device 220 may be placed at theintended marking point 210. Once the marking device 220 is turned on,the light emitted from the tip of the marking device 220 would beperceived as if the light were originated from the marking point 210. Inone implementation, the turning on of the marking device 220 may causethe marking mode of the image device 180 to be switched on.

In another scenario, the marking device 220 may be a pen like device andmay be pressed against the surface 110. The pressing of the tip of themarking device 220 against the surface 110 may turn on thelight-emitting function of the marking device 220. Since the tip of themarking device 220 emits light in all directions and is in physicalcontact with the surface 110, the point of physical contact becomes themarking point 210 from the perspective of the image capturing part 150.In other words, as long as the tip of the marking device 220 is pressedagainst the surface 110, the marking device 220 may be used as a pen forwriting and drawing, and the movement of the marking device 220 iscaptured as a set of marking points 210.

FIG. 3 illustrates an operational scenario in utilizing a marking deviceto place marking points on a projected image, in accordance with atleast some embodiments of the present disclosure. In FIG. 3, a firstpresentational slide 310 is generated and projected by an image deviceto a surface. After placing marking points on the first presentationslide 310 with a marking device, the image device is configured todetect the marking points, generate a second presentation slide 320, andproject the second presentation slide 320 to the surface to replace thefirst presentation slide 310. When additional marking points are placedon the second presentation slide 320, a third presentational slide 330can be similarly generated.

To further illustrate, suppose a marking device adapted for utilizingone of the various approaches described above to draw an ellipse 321 onthe first presentation slide 310. The image device can record thedrawing of the ellipse 321 by repeatedly capturing an image of thesurface and processing the captured image. Each of the captured imagesis processed to detect the existence and the location of a singlemarking point. The detected marking point is used to modify the imagebeing projected. After modification, the modified image is thenprojected to the surface, and the image device is configured to captureanother image for the detecting of another marking point. Thus, themarking points detected from the repeatedly captured images areaccumulated and included in an image to be projected. For example,comparing to the first presentation slide 310, the second presentationslide 320 includes a graphical ellipse 321 at a location based on themarking points detected in the captured images. Other graphic elementssuch as, without limitation, lines, circles, and boxes, may beformulated by accumulating multiple detected marking points.

Similarly, the image device may be configured to record or capture theprocess of drawing a box 331 on the second presentation slide 320 bycapturing multiple images of the surface within a time interval anddetecting the marking points from the multiple captured images. Based onthe detected marking points, the image device may generate the box 331and modify the second presentation slide 320 to include the box 331before projecting the modified presentation slide, or the presentationslide 330.

FIG. 4 illustrates a flow diagram of an example process 401 forcapturing and displaying marks on a projected image, in accordance withat least some embodiments of the present disclosure. The process 401 maybe performed by processing logic that may comprise hardware (e.g.,special-purpose circuitry, dedicated hardware logic, programmablehardware logic, etc.), software (such as instructions that can beexecuted on a processing device), firmware or a combination thereof. Inone embodiment, machine-executable instructions for the process 401 maybe stored in memory 170 of FIG. 1, executed by the processor 160 of FIG.1, and/or implemented in an image device 180 of FIG. 1.

In one embodiment, an image device performs functions of the process 401by projecting a first image to a surface, capturing a second image fromthe reflective image, detecting a marking point in the second image anddetermining location information of the marking point, generating athird image by adding a graphic element to the first image based on thelocation information, and projecting the third image to the surface inreplacement of the first image.

At operation 410, an image device generates a first image and projectsthe first image to a surface. An image processor of the image device maygenerate the first image and transmit the generated image to an imageprojecting part of the image device. The image projecting part then mayproject the first image to the surface. All pixels of the first imagemay be in white, resulting in a white board being displayed on thesurface. In one implementation, a marking device is configured to placemarking points on the first image. The marking device may also signalthe image device to start capturing images from the surface to detectlight emitted from the marking device.

At operation 420, a second image, which may contain a marking point, iscaptured from the surface by an image capturing part of the imagedevice. In one implementation, the image capturing part of an imagedevice is a video capturing device. The captured video can then beforwarded to the image processor of the image device and be processedframe-by-frame, with each of the frames of the video being treated asthe second image. Alternatively, the image device may sample some of theframes and treat each of the sampled frames as the second image. Forexample, if each second of a video contains 30 frames, the image devicemay select 10 out of the 30 frames in each second as the second images.Such an approach could reduce resource consumption in the image devicewhen no marking point has been detected from the video frames for aperiod of time. The image device may also be configured to capture asecond image for every predetermined and configurable interval (e.g.,every 10 ms).

At operation 430, the image processor of the image device processes thesecond image captured at operation 420 and tries to detect whether amarking point is present in the second image. In one implementation, theimage processor may compare the projected first image and the capturedsecond image for differences. The differences of these two images canthen be identified as the pixels that represent the light emitted from amarking device. During comparison, the respective pixels or groups ofpixels from the first image and the second image are compared based oncolor, brightness, and other factors. Since some noises from other lightsources in the projecting environment may also be captured by the imagedevice, the above comparison may take the captured noises intoconsideration during comparison. For example, if a pixel from the firstimage is associated with a color or brightness value that is within acertain tolerance level comparing to a corresponding pixel in the secondimage, the two pixels may be deemed identical.

In another implementation, the marking point may be detected byevaluating the brightness of the pixels in the captured second image.For example, the captured second image may contain pixels that areeither brighter or dimmer than the corresponding pixels in the projectedfirst image. The dimmer pixels may be shadows on the surface that areresulted from blocking of the projected image by objects or humanbodies. However, when a marking point is introduced into the viewingfield of the image capturing part, the addition of light sourceincreases the brightness of the pixels for the marking point. Thus, themarking point can be detected by identifying the pixels in the capturedsecond image that are brighter than the corresponding pixels in theprojected first image.

In yet another implementation, the marking point may be detected byevaluating the pixels in the captured second image, without utilizingthe projected first image. For example, when a filter is installed toallow in only the light emitted from the marking device, the markingpoint can be easily detected by identifying the pixels in the capturedsecond image that has a certain level of brightness. In another example,when the first image is utilized as a white board, any pixels with anon-white color would be treated as pixels for marking points.

If a marking point is detected at operation 430, then the locationinformation of the marking point is also determined by the imageprocessor. The location information describes where the pixels for themarking point are located in the captured image. For example, thelocation information can contains all the pixels that are deemed part ofthe marking point, as well as these pixels' address and colorinformation. If no marking point is detected at operation 430, then theprocess 401 proceeds to operation 420 to capture additional images. If amarking point is detected, then process 401 proceeds to operation 440.

At operation 440, the image processor of the image device generates athird image based on the marking point and its location information inthe captured second image. In one embodiment, the third image isgenerated by adding a graphic element to the projected first image at alocation corresponding to the location of the marking point in thecaptured second image. For example, the image processor can modify thefirst image by changing the color and intensity of the pixels of thefirst image at the location corresponding to the location of the markingpoint in the second image. Also, a graphic element can be formed withpixels with different color, shape, or brightness, and can be used toreplace the original pixels in the first image at a similar location.Alternatively, a predetermined symbol, such as a graphic icon, a squareor round object, can be utilized as a graphic element and be placed inthe third image at a similar location as the location of the markingpoint in the second image. To differentiate the graphic element to bedisplayed on the surface from the new marking point that will begenerated by the marking device, the graphic element may have adifferent color, shape, brightness, or spectrum comparing to the markingpoint.

At operation 450, the third image generated at operation 440 isprojected by the image device to the surface in replacement of the firstimage. Since the third image is generated with a graphic element beingplaced at a location designated by the marking point, once projected,the third image looks as if a graphic element is placed on the projectedimage at a particular location by the marking device. Further, the aboveoperations can be repeated to capture a sequence of marking points, anddisplay complicated graphic elements, such as lines, circles, andcharacters, on the surface. For example, when a first image containspreviously generated graphic elements, and the subsequent markingprocess generates a second graphic element to be placed next to thepreviously generated graphic elements, then the resulted image containsmultiple graphic elements that can form a part of a line or a circle.Alternatively, a sequence of marking points can be detected before athird image is generated with a set of graphic elements corresponding tothe sequence of marking points.

In one embodiment, the movement of the marking points can be saved forfurther usage. When a set of marking points are detected during apredetermined period of time, this set of marking points can beevaluated to extract certain movement patterns. The movement patternscan then be used to trigger additional computer functions. For example,if a pattern of the marking points shows a circular movement at aparticular location, the detected pattern can be used to trigger aspecific computer operation, such as displaying a next slide of apresentation.

FIG. 5 illustrates a flow diagram of an example process 501 forcalibrating, capturing and displaying marks on a projected image, inaccordance with at least some embodiments of the present disclosure. Theprocess 501 can be performed by processing logic that may comprisehardware (e.g., special-purpose circuitry, dedicated hardware logic,programmable hardware logic, etc.), software (such as instructions thatcan be executed on a processing device), firmware or a combinationthereof. In one embodiment, machine-executable instructions for theprocess 501 can be stored in memory 170 of FIG. 1, executed by theprocessor 160 of FIG. 1, and/or implemented in an image device 180 ofFIG. 1.

In one embodiment, an image device performs functions in the process 501by calibrating a projecting field of an image projecting part and aviewing field of an image capturing part of the image device. Aftercalibration, the image projecting part of the image device projects afirst image to a surface. Optionally, a filter can be used inconjunction with the image capturing part to filter light passingthrough the image capturing part's viewing field. The image capturingpart can capture a second image from the surface. The image device thendetects whether a marking point exists in the second image. If themarking point exists, then the image device determines a location of themarking point in the second image, and modifies the first image byplacing a graphic element at a location corresponding to the location ofthe marking point in the second image. Afterward, the first image isreplaced with the modified image, and the process 501 can repeat theabove operations starting from operation 520.

At operation 510, a calibration process can be optionally performed toalign the projecting field of the image projecting part with the viewingfield of the image capturing part of an image device. Aligned projectingfield and viewing field reduce the amount of processing required incomparing the projected image with the captured image during markingpoint detection. In calibration process, the image projecting part canproject a special image, which contains specific image patternsdescribing the boundaries of the projecting field, to the surface. Theimage capturing part can then capture an image from the surface, and tryto detect these patterns in the captured image. For example, theprojected image can contain lines marking the four corners of theprojected field. Upon capturing the image through the image capturingpart, the image device can ascertain these four corners of theprojecting field, and adjust the viewing field accordingly in order tomatch the projecting field with the viewing field. The adjustment can beaccomplished by physically fine-tuning the image capturing part, or bysoftware approaches.

At operation 520, the image projecting part projects a first image to asurface similar to operation 410 of FIG. 4. At operation 530, a filteris optionally placed in front of the image projecting part. If thefilter can filter out all other spectrums of light and let-in only thespecific light emitted from the marking device, then the subsequentmarking point detection operation can be greatly simplified. At 540, theimage capturing part of the image device captures a second image fromthe surface similar to operation 420 of FIG. 4. The captured secondimage may contain marking points emitted from the marking device. At550, the captured second image is transmitted from the image capturingpart to the image processor of the image device. In operation, themarking point is detected by the image processor as described above. At560, the location information of the marking point is also determined bythe image device. At 570, based on the marking point detected atoperation 550, and the location information ascertained at operation560, the first image of operation 520 is modified by placing a graphicelement at a location corresponding to the location of the marking pointin the second image. At operation 580, the first image is replaced bythe image device with the modified image. Afterward, process 501 canoptionally proceed to operation 520, in which the modified first image,which contains the added graphic element, is projected onto the surface.Thus, process 501 can proceed to detect additional marking points.

There is little distinction left between hardware and softwareimplementations of aspects of systems; the use of hardware or softwareis generally (but not always, in that in certain contexts the choicebetween hardware and software can become significant) a design choicerepresenting cost vs. efficiency tradeoffs. There are various vehiclesby which processes and/or systems and/or other technologies describedherein can be effected (e.g., hardware, software, and/or firmware), andthat the preferred vehicle will vary with the context in which theprocesses and/or systems and/or other technologies are deployed. Forexample, if an implementer determines that speed and accuracy areparamount, the implementer may opt for a mainly hardware and/or firmwarevehicle; if flexibility is paramount, the implementer may opt for amainly software implementation; or, yet again alternatively, theimplementer may opt for some combination of hardware, software, and/orfirmware.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, or examples can be implemented,individually and/or collectively, by a wide range of hardware, software,firmware, or virtually any combination thereof. In one embodiment,several portions of the subject matter described herein may beimplemented via Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs), digital signal processors (DSPs), orother integrated formats. However, those skilled in the art willrecognize that some aspects of the embodiments disclosed herein, inwhole or in part, can be equivalently implemented in integratedcircuits, as one or more computer programs running on one or morecomputers (e.g., as one or more programs running on one or more computersystems), as one or more programs running on one or more processors(e.g., as one or more programs running on one or more microprocessors),as firmware, or as virtually any combination thereof, and that designingthe circuitry and/or writing the code for the software and or firmwarewould be well within the skill of one of skill in the art in light ofthis disclosure. In addition, those skilled in the art will appreciatethat the mechanisms of the subject matter described herein are capableof being distributed as a program product in a variety of forms, andthat an illustrative embodiment of the subject matter described hereinapplies regardless of the particular type of signal bearing medium usedto actually carry out the distribution. Examples of a signal bearingmedium include, but are not limited to, the following: a recordable typemedium such as a floppy disk, a hard disk drive, a Compact Disc (CD), aDigital Video Disk (DVD), a digital tape, a computer memory, etc.; and atransmission type medium such as a digital and/or an analogcommunication medium (e.g., a fiber optic cable, a waveguide, a wiredcommunications link, a wireless communication link, etc.).

Those skilled in the art will recognize that it is common within the artto describe devices and/or processes in the fashion set forth herein,and thereafter use engineering practices to integrate such describeddevices and/or processes into data processing systems. That is, at leasta portion of the devices and/or processes described herein can beintegrated into a data processing system via a reasonable amount ofexperimentation. Those having skill in the art will recognize that atypical data processing system generally includes one or more of asystem unit housing, a video display device, a memory such as volatileand non-volatile memory, processors such as microprocessors and digitalsignal processors, computational entities such as operating systems,drivers, graphical user interfaces, and applications programs, one ormore interaction devices, such as a touch pad or screen, and/or controlsystems including feedback loops and control motors (e.g., feedback forsensing position and/or velocity; control motors for moving and/oradjusting components and/or quantities). A typical data processingsystem may be implemented utilizing any suitable commercially availablecomponents, such as those typically found in datacomputing/communication and/or network computing/communication systems.

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures aremerely exemplary, and that in fact many other architectures can beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected”, or“operably coupled”, to each other to achieve the desired functionality,and any two components capable of being so associated can also be viewedas being “operably couplable”, to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents and/or wirelessly interactable and/or wirelessly interactingcomponents and/or logically interacting and/or logically interactablecomponents.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to inventions containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.”

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopeand spirit being indicated by the following claims.

We claim:
 1. A method for marking a first image projected to a surface,comprising: capturing, by an image capturing component of an imagedevice, a second image from the surface; detecting a marking point inthe second image, wherein the marking point is generated by a markingdevice, placed on a viewing path between the image capturing componentand the surface, emitting light toward the image capturing component;and generating a third image by placing a graphic element in the firstimage at a location corresponding to a location of the marking point inthe second image.
 2. The method as recited in claim 1, furthercomprising: projecting the third image to the surface to replace thefirst image.
 3. The method as recited in claim 2, further comprising:capturing a fourth image from the surface, on which the third image isdisplayed; detecting a second marking point in the fourth image;generating a fifth image by placing a second graphic element in thefourth image; and projecting the fifth image to the surface to replacethe third image.
 4. The method as recited in claim 3, wherein the firstimage and the third image are generated by an image projecting componentof the image device, and the fourth image is captured by the imagecapturing component of the image device.
 5. The method as recited inclaim 4, further comprising: calibrating the image device by aligning aviewing field of the image capturing component with a projecting fieldof the image projecting component.
 6. The method as recited in claim 1,wherein the detected marking point is perceived by the image capturingcomponent as a point reflected from the surface.
 7. The method asrecited in claim 1, wherein the marking device emits the light when atip of the marking device is being pressed against the surface.
 8. Themethod as recited in claim 1, wherein the detecting of the marking pointcomprising filtering the light emitted by the marking device.
 9. Themethod as recited in claim 1, wherein the detecting of the marking pointcomprising finding a difference between the first image and the secondimage, the marking point being associated with the difference.
 10. Themethod as recited in claim 1, wherein the detecting comprisingidentifying pixels in the second image that have different colorscomparing to corresponding pixels in the first image.
 11. The method asrecited in claim 1, wherein the method is embodied in a machine-readablemedium as a set of instructions which, when executed by an imageprocessor, cause the image processor to perform the method.
 12. A methodfor marking a first image projected to a surface, comprising: capturinga second image from the surface; detecting a marking point in the secondimage, the marking point being associated with a difference detected bycomparing the first image and the second image; determining a locationof the marking point in the second image; modifying the first image togenerate a third image by placing a graphic element at a locationcorresponding to the location of the marking point in the second image;and projecting the third image to the surface to replace the firstimage.
 13. The method as recited in claim 12, wherein the graphicelement is associated with a degree of transparency.
 14. The method asrecited in claim 12, further comprising receiving a request to enter amarking mode prior to the capturing.
 15. The method as recited in claim12, wherein the marking point is generated by a human-invisible lightsource.
 16. A system configured to mark an image, comprising: an imageprojecting component configured to project a first image to a surface;an image capturing component configured to capture a second image fromthe surface; and an image processor coupled with the image projectingcomponent part and the image capturing component, wherein the imageprocessor is configured to detect a marking point in the second imageand to modify the first image to generate a third image by adding agraphic element at a location corresponding to a location of the markingpoint in the second image, the marking point being associated with adifference detected by comparing the first image and the second image.17. The system as recited in claim 16, further comprising a filtercoupled with the image capturing component to detect the marking pointfrom the second image.
 18. The system as recited in claim 16, whereinthe marking point corresponds to a point on the surface that isidentified by a light beam and within the boundary of the first image.19. The system as recited in claim 16, wherein the marking point isgenerated by a marking device, placed on a viewing path between theimage capturing component and the surface, emitting light toward theimage capturing component.
 20. The system as recited in claim 16,wherein the image processing component is further configured to detectthe marking point by finding pixels in the second image that havedifferent colors comparing to corresponding pixels in the first image.